4th gear lock-up issue...

Covers all sn94/95 mustang v8 ecu's.
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

I'll load a couple of fuel changes into what you sent and let you know when it comes back from the pipe shop later this week.
Thank you very much again. Other than the LU issue I'm extremely happy with the trans swap and with your base tune. I'll let you know.
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

Soon as it comes back from the pipe shop I'll add a couple of recent fuel changes and let you know. Once again I can't say thanks enough...but I'll try.
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

Well, I'm sorry to report...no joy. It still works as it should in 3rd gear but locks up then unlocks after a few seconds in 4th.
decipha
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Re: 4th gear lock-up issue...

Unread post by decipha »

make sure your 4th gear unlock speed is lower than your lock speed
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

35.5 Lock, 34.0 unlock. Rel TP is 52 Lock, 124 unlock.
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

Is there any chance this could be due to a PCM fault? Doesn't seem likely since 3rd gear LU works as it should and all the electrical checks out.
decipha
Posts: 714
Joined: 15 Feb 2021, 12:23
Location: New Orleans, LA
Vehicle Information: 10x Supercoupes
Lincoln LS 5spd
Ls1 t56 ss camaro
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gmc 2500hd classic
gt40p explorer
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Re: 4th gear lock-up issue...

Unread post by decipha »

no its not the ecu

can u pull codes to see if its throwing anything?
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

I've pulled them a number of times as I got this thing on the road...nothing suspicious. When it quit doing trying to lock up in any gear a week or so ago I cleaned the J3 contacts and it went back to working in 2nd and 3rd. I've even put a DVM across Pin 53 to ground. Ign. on full Vpower. In LU, about 10.5V which would indicate the resistance of the TCC solenoid. Those values also correspond to the indications of slip ratio and BCSDC during lock and unlock.

Okay it is showing a 628 (converter clutch excessive slippage) It did this the last time it refused to show a LU signal but that code went away when I cleaned the J3 and 3rd LU started working again. Tomorrow I'll check the TCC/Pin 53 circuit with the VOM and make sure it's good. Thanks again, LYK.
decipha
Posts: 714
Joined: 15 Feb 2021, 12:23
Location: New Orleans, LA
Vehicle Information: 10x Supercoupes
Lincoln LS 5spd
Ls1 t56 ss camaro
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gmc 2500hd classic
gt40p explorer
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Re: 4th gear lock-up issue...

Unread post by decipha »

thats got nothing to do with the j3 if it keeps coming up with exc slip then the converter might be bad
MyShrink66
Posts: 23
Joined: 26 Feb 2021, 08:54
Location: Montrose, Colorado
Vehicle Information: 1966 Mustang HT, 5.0/4R70W, CBAZA

Re: 4th gear lock-up issue...

Unread post by MyShrink66 »

I agree but it has only come up with 628 when it was not sending the LU ground signal from the ecu, Two times. And when it is sending the signal why will it function in 3rd gear but not 4th? I'll be doing more elect. testing tomorrow. LYK. This not sending the signal at all until I remove/replace the Moates makes me wonder...
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